$width: 400px;

@import  "./app.scss";

@mixin blackTheme(){
    background-color: black;
    color: white;
}

#box {
  width: $width;
  .item {
    width: calc($width / 4);
    @include setCenter(40px);
    @include blackTheme;
  
  }
}
.menu{
  display: flex;
  .item{
    flex: 1;
    @include setCenter(40px);
    @include blackTheme;
  }
  .active{
    background-color: red;
  }
}

